1997 z3 failed smog 46000 orig miles only

[Unregistered]

Went to test only station (Calif). Never had a problem before. Put 1 quart of acetone in 1/2 full gas tank and drove 60 miles. It passed on the 25 mph part of the test but failed on the 15 mph.
NO was over the max. Tested at 578 AND should have been under 459. Do you think that the acetone was to much and caused this issue? Any suggestions? Normally I run regular unleaded in
this little car. Also note the test guy put the probe in the tail pipe and the put a traffic orange cone next to the tailpipe edge to keep the probe from falling out... could immediate proximity of the cone to the tail pipe obstruct flow on 15 mph test just enough to alter readings?

thanks bob

[vintage42]

... Put 1 quart of acetone in 1/2 full gas tank... failed on the 15 mph... Do you think that the acetone was to much and caused this issue? Any suggestions? Normally I run regular unleaded...

Why not use premium like the manual says? What is the matter with your engine that it won't pass, and why do you think acetone helps?

When the fuel gauge says 1/2, the tank is actually down 2/3, leaving about 4 gallons. One quart of acetone in 4 gallons of gas seems like a pretty strong solvent mixture that would erode and weaken plastic and rubber in the fuel system.

[Unregistered]

To Vintage 42

Took your advice and filled up tank with Premium. Then drove for 30 miles, then took back to smog guy... failed again with 100+ additional negative
points on the NOx... so the acetone actually was better than pure premium.

But now I have to start trouble shooting. Will start with cleaning egr valve....but I don't see anything like it on this 1997 z3 1.9. Do you know the location-- can you send a photo?

Sincerely,
bob

[vintage42]

I see you are posting the problem on both ********** and Bimmerforum. Very active forums with knowledgeable people. You should get good answers there. I don't think the 1.9 M44 engine has exhaust gas recirculation. It also has no air pump.

[Robert Platt Bell]

To Vintage 42

Took your advice and filled up tank with Premium. Then drove for 30 miles, then took back to smog guy... failed again with 100+ additional negative
points on the NOx... so the acetone actually was better than pure premium.

But now I have to start trouble shooting. Will start with cleaning egr valve....but I don't see anything like it on this 1997 z3 1.9. Do you know the location-- can you send a photo?

Sincerely,
bob

Did you use your code reader to see if any OBD II codes were being thrown? Most auto parts shops will read codes for free.

Could be anything from bad O2 sensors to an intake leak to a bad catalytic converter.

Without a code reader you are flying blind and just attacking random parts is probably not the way to go.


I am guessing O2 sensors, even though they are supposed to last 100,000 miles, they do fail with age as well.

But remember just because the computer shows an error code mentioning a part by name DOES NOT mean that part is what is wrong.

For example, "O2 sensor out of range" may be a leak in the rubber intake elbow.

Or "Catalytic Converter Efficiency below threshold" may mean the primary O2 sensors are shot.

Google the code and your model number and you'd be surprised what you will find online. Good Luck!

[Carlín96/M44]

Went to test only station (Calif). Never had a problem before. Put 1 quart of acetone in 1/2 full gas tank and drove 60 miles. It passed on the 25 mph part of the test but failed on the 15 mph.
NO was over the max. Tested at 578 AND should have been under 459. Do you think that the acetone was to much and caused this issue? Any suggestions?

Since new I have always used Regular 87 Octane gas, in my 96 - E36...no problems passing emission, but in CA is more stricter in comparison with other states. The only thing I used every 1,000 miles is fuel injector cleaner I don't know in your case will help. The crank case vent valve (EGR) in our engines is located on the driver side top of the intake manifold is round flat black in color and made of plastic with one vent hose. I usually change mine once a year due to the amount of dust here in south west.

[vintage42]

... I don't think the 1.9 M44 engine has exhaust gas recirculation. It also has no air pump.

Correction on the second statement: the 1.9 was equipped with a secondary air pump (SAP) in Jan 1997. My 1997 1.9 built in Oct 1996 does not have one.

[prdz3]

Check to be sure the little vacuum hose-type hose isn't broken or cracked where it goes into the secondary air pump. Happened on my '97 1.9, but it threw a code. It's an easy thing to check though; just need to open the hood and look.

[UncleDavid]

Did you put the car through the driving cycle ? If you disconnect the battery, the memory is wiped clean. This is the first step you put a 1.9l through before emissions. Google the chart; the table's periods and speeds are not sequential. Always run the HIGHEST octane available.